Cloud and pour point of lubricant, Chemical Engineering

Q. Write short notes on cloud and pour point of lubricant.

Ans. Cloud and pour point of lubricant: When the temperature is lowered up to a particular point, the oil becomes cloudy in appearance. This temperature is called cloud point. When the temperature is further lowered up to a certain temperature, the oil ceases to flow or pour or becomes semisolid. This temperature is known as pour point. Important example of cloud and pour points are refrigerator plants and aircraft engines, which may be required to start and operate at and sub zero temperatures. The apparatus employed for the determination of pour point is pour point apparatus. It consists of following parts:

1.      Flat bottomed tube: It is made of glass and has standard dimensions.

2.      This tube is enclosed in a glass or metal jacket which is firmly fixed in a cooling bath having suitable freezing mixture.

Working: Test oil is filled inside the tube. Thermometer is adjusted inside the oil and in the cooling bath and cork bath is fitted to the mouth of flat bottomed tube. The tube is then kept in the freezing mixture. The freezing mixture is prepared as below:



Temperature range


Ice + water

Up to + 100C


Ice + NaCl

Up to - 100C


Ice + CaCl2

Up to - 250C


Solid CO2 + Acetone

Up to - 600C

With every degree fall of temperature of oil, the tube is taken out and observed for a moment. The temperature, at which hazy appearance give cloud points. Cooling process is continued till oil stop flowing. That temperature is pour point.

Posted Date: 7/21/2012 8:02:58 AM | Location : United States

Related Discussions:- Cloud and pour point of lubricant, Assignment Help, Ask Question on Cloud and pour point of lubricant, Get Answer, Expert's Help, Cloud and pour point of lubricant Discussions

Write discussion on Cloud and pour point of lubricant
Your posts are moderated
Related Questions
Introduction : You will recall previous study of this course about the various duties and activities of a lab staff that facilitate management of the laboratory in an efficient ma

Wet air containing 4.0 mole% water vapor at 76°F and 14.8 psia is passed through a column of calcium chloride pellets. The pellets absorb 97% of the water and none of the other con

Normal 0 false false false EN-IN X-NONE X-NONE

Drift current is the electric current, or movement of charge carriers, which is because of the applied electric field, often stated as the electromotive force over a given distanc

prove that work is a path function

PROCEDURE : Visit any lab (physics, chemistry or biology) of your study centre or any other you can get access to and note its features. To guide you through we have listed below

You get excellent learning approach for preparing your standard exams by well trained qualified experts, At Expetsmind, you can take help in various courses, assignments, and get a

A mixture of calcium sulfate (CaSO4) and calcium uranate (CaUO4) contains 10% sulfur by mass. What is the mass percentage of uranium in the mixture?

Consider the cascade loop as shown below: i)   Specify the inner-loop gain such that the damping coefficient of the closed loop is equal to 0.4 ii)  Derive the ultimate